1. Field of the Invention
This invention relates to an outrigger for a boom truck or the like and more particularly to a dual mode outrigger for a boom truck or the like.
2. Description of the Related Art
Many types of outriggers or stabilizers have been previously provided for boom trucks, utility trucks, cranes, or the like. One type of prior art outrigger, commonly referred to as an “A-frame” outrigger is disclosed in U.S. Pat. No. 3,262,582. In the '582 structure, the upper end of a tubular leg section 232 is pivotally secured to a bracket unit 226 positioned at one side of the vehicle 24. A lower leg section 234 telescopes over section 232. Hydraulic cylinder 238 is positioned within leg sections 234 and 232 to cause leg section 234 to slidably move with respect to leg section 232. A pair of parallel links 256 are pivotally secured to leg section 234 and housing 216 by a pin means. In the stowed position, as seen in FIG. 5 of the '582 patent drawings, with cylinder 238 retracted, the leg sections 232 and 234 are positioned adjacent the side of the vehicle in a generally vertically disposed attitude. When hydraulic cylinder 238 is extended, the sections 232 and 234 swing outwardly about pivot pin 230, due to the action of the parallel links 256, so that the lower end of section 234 is positioned laterally outwardly of the vehicle, as seen in FIG. 3 of the '582 patent. In the '582 outrigger, extension of the hydraulic cylinder 238 always causes the outrigger to swing outwardly from the side of the vehicle. In other words, the leg sections cannot be maintained in the position of FIG. 5 of the '582 patent when the hydraulic cylinder 238 is extended.
In recent years, the A-frame outriggers have been lengthened and modified so that the lower ends of the outrigger may be positioned many feet laterally of the vehicle. In the typical A-frame outrigger of the prior art, the ground-engaging pad or shoe is spaced a considerable distance from the side of the vehicle. If the vehicle is positioned at one side of a roadway or the like, the outrigger at the street side of the vehicle extends many feet out onto the street or roadway, when deployed, thereby creating a traffic problem. If the street side outrigger cannot be deployed, it is impossible to level or stabilize the vehicle.